The subject invention provides for a new and improved milling cutter having a unique axial locating wedge and insert assembly which permits the axial position of the insert to be regulated.
In the prior art, milling cutters are provided for machining metal parts made of cast iron, aluminum or steel. The prior art milling cutters are generally circular in configuration and are adapted to be rotated around a central axis. The cutters are provided with a plurality of insert pockets disposed around the periphery thereof, which are adapted to receive indexable cutting inserts, each insert having a plurality of sharpened cutting edges. The inserts must be securely clamped within the pockets and accurately located to define a constant axial plane and radial outer diameter. Stated differently, in order to provide a clean, smooth, machined cut, all the inserts in the cutter body are adjusted such that their cutting edges define a constant tracking and circular outer diameter in both the axial and radial planes.
In order to accurately locate and maintain the indexable inserts within each pocket, various wedge assemblies have been employed which are mounted in the cutter pockets along with the inserts. More specifically, locking wedges have been provided which are interposed between the insert and the insert pocket to clamp the insert securely within the pocket during the cutting operation. This type of simple locking wedge arrangement is sufficient when all the inserts utilized have standard and constant dimensions. For example, in a conventional machining operation, when the cutting edges of the inserts become worn or chipped, the operator merely has to loosen the wedges and rotate or index the inserts to expose a fresh cutting edge. In this procedure, wherein the dimensions of the insert remain relatively constant, the inserts are merely discarded after all the edges have become worn. However, with the increasing use of diamond or borazon inserts, which have a relatively high initial cost, it has been necessary to regrind or relap the worn cutting dish and/or flank edges to extend the life of the insert. The regrinding alters the dimensions of the inserts such that it becomes impossible to maintain a uniform outer diameter in a boring cutter with fixed, non-adjustable pockets. When a uniform outer diameter and axial tracking cannot be maintained, serious run out problems occur which result in uneven and inaccurately machined parts.
In a copending application, U.S. patent application Ser. No. 138,197, filed Apr. 7, 1980, assigned to the same assignee as the subject invention, an improved method for dealing with insert position problems is disclosed and includes a means for adjusting the radial position of an insert within a fixed cutter body, and may be utilized to control critical insert to wedge overhang. The means disclosed in the latter application, the contents of which are incorporated herein by reference. include an adjustable insert seat having an L-shaped cut out on one surface thereof for receiving the indexable insert. A means is provided to adjust the radial position of the insert seat, which in turn, adjusts the radial position of the insert. While this adjustable insert seat functions to eliminate many of the problems associated with insert to wedge overhang, it would be desirable to provide an insert seat which is capable of radial adjustment to correct for tracking errors introduced with reground inserts, while maintaining the original characteristics of the cutter. Other examples of wedge assemblies which provide a degree of adjustability in a single plane can be found in U.S. Pat. No. 3,708,843, to Erkfritz, issued Jan. 3, 1973, and French Pat. No. 2,406,493 issued May 18, 1979. While the latter patents provide for adjustability in a single plane, it would also be desirable to provide an adjustable wedge assembly which can compensate for tracking errors in both the axial and radial planes to produce a consistant depth of cut plane and circular outer diameters.
Accordingly, it is an object of the subject invention to provide a new and improved locating wedge and insert assembly which permits the accurate adjustment of the axial position of the insert.
It is a further object of the subject invention to provide an adjustable locating wedge and insert assembly wherein an adjustable locating wedge is provided which is aligned and in abutting relationship with the lowermost cutting edge of the insert such that when the axial position of the wedge is varied, the axial position of the insert is varied.
It is another object of the subject invention to provide an adjustable locating wedge and insert assembly which includes both an axially locating wedge and an adjustable insert seat such that both the axial and radial position of the insert can be adjusted to eliminate run out problems and provide accurate and smooth machining.
It is still a further object of the subject invention to provide an adjustable locating wedge and an indexable insert assembly which may be employed to adjust a plurality of randomly sized, reground inserts in fixed insert pockets of a milling cutter.